The overall objective of this project is to determine the cellular immune status of a group of 300 healthy individuals over the age of 70 in an attempt to find if depressed immune function in this population correlates with subsequent morbidity and mortality. Additional studies funded by this grant include investigations of the effects of in vivo administration of prostaglandin synthetase inhibitors to normal young and elderly volunteers on their cellular and humoral immune responses. In addition we are continuing our studies on the mechanism of inhibition by prostaglandins of lymphocyte function.